1. Field of the Invention
The present invention is concerned with a greatly improved imprinting device capable of printing at very high speeds permitting the device to be used as a machine printer, while at the same time being sufficiently simple and low in cost that it can be employed as a conventional typewriter in a home or office. More particularly, it is concerned with such a device which accomplishes printing, word spacing and tab spacing using a single mainspring as a source of motive energy and in such manner that a limited energy quantum is withdrawn from the mainspring and distributed during each printing and/or spacing cycle in the most efficient manner. Energy distribution is effected such that energy remaining after the required energy for actual printing purposes is determined is employed to increase the speed of translation along the page; in this way a variable but statistically very high printing speed is obtained.
2. Description of the Prior Art
The typewriter art is highly developed and over a century old. At the outset of typewriter development, the devices were for the most part strictly mechanical typewriting machines of various degrees of complexity and sophistication. In more recent times these mechanical or manual machines have been largely replaced by electrically powered typewriters. In all cases however, the goal has been to achieve sufficient typing speed along with consistently good printing qualities.
With the advent of the electronic age, and particularly the development of high speed computers and information processing equipment, a need arose for a printing device having capabilities greatly different from those required of a conventional manual or electric typewriter. For example, while a fifteen character per second typing speed is more than adequate for a typewriter, this rate is exceedingly slow when contrasted with the output rates of computers or the like. In response to the need for high speed printing devices, a number of units have been proposed. Among these are dot printers, ink jet printers, chain printers, laser printers, daisy printers, modified electric typewriter printers, line printers and xerographic printers. While a number of these devices have achieved substantial commercial success for their intended function, they are in general characterized by a high degree of mechanical, electric and/or electronic complexity, and concomitant high cost. Further, most of these units are simply not realistically usable as a typewriter, inasmuch as they have poor printing quality, obscure the line of write as printing proceeds, or are incapable of making carbon copies.
In short, conventional manual or electric typewriters are adequate for normal typewriting and can be purchased at a reasonable cost, but are too slow or too expensive to convert to machine printers; on the other hand, printers developed specifically for coupling to remote input from computers, magnetic recordings, phone couplings or the like are in general far too expensive to justify use thereof as a typewriter, even if this were a functional possibility.
The problems outlined above have presented a serious obstacle to the spread of small computers and remote terminals linked to large central computers. Thus, while an individual or small company may be willing to invest in a small computer or terminal, the cost of a conventional machine printer as a part thereof may be such as to make the package price prohibitive. On the other hand, if a low cost typewriter/printer were available, the effect upon the spread of computer technology and other data processing equipment would be considerable.
Hence, there is a real and heretofore unsatisfied need in the art for a low cost, high speed printing device usable without modification either as a conventional typewriter or machine printer.